Fluid is circulated in automotive vehicles and other systems via a flow device. The flow device is typically a pump for liquids or coolants and a blower or fan when air is the cooling medium. The circulated fluid can be used to perform thermal management or fluid actuation functions. For instance, certain vehicle powertrains use a relatively high-voltage battery module as a source of electrical energy for powering one or more electric traction motors. The battery module and associated power electronics generate substantial amounts of heat during sustained use. Therefore, circulated fluid in the form of air or coolant is used to regulate the operating temperature of these components. Additionally, heating, ventilation, and air conditioning (HVAC) blowers are used to move air into and out of a vehicle cabin. In other applications, fluid may be circulated under pressure via a pump to provide a source of fluid power to a point of use, for instance to actuate a valve or a piston. Knowledge of the functional state of a given flow device is therefore essential to the overall control of the system.